RESUMO
Patients with a first episode of schizophrenia generally have increased phospholipid membrane breakdown products within the brain, while findings in chronic patients have been inconsistent. In this study we examine progressive changes in phosphorus membrane metabolites in the same patient group through the early years of schizophrenia in brain regions associated with the disease. Sixteen never-treated and medicated first episode schizophrenic patients were assessed at 10 months and 52 months after diagnosis. Sixteen matched volunteers were assessed at baseline and after 35 months. Phospholipid membrane metabolism was assessed with phosphorous magnetic resonance spectroscopy in the thalamus, cerebellum, hippocampus, anterior/posterior cingulate, prefrontal cortex, parieto-occipital cortex, superior temporal gyrus and temporal pole. At 10 months, glycerophosphocholine was increased in the anterior cingulate in patients as compared to controls. Glycerophosphocholine was decreased in the anterior cingulate and increased in the posterior cingulate and left superior temporal gyrus; glycerophosphoethanolamine was decreased in the left thalamus and increased in the left hippocampus within patients over time. At 52 months, compared to controls phosphocholine was increased in the left thalamus and glycerophosphoethanolamine was increased in the left hippocampus. These results imply a gradual inclusion of brain regions in schizophrenia where an initial increase, followed by a decrease in phospholipid membrane metabolites was observed. This pattern, observed in the early years of schizophrenia, is consistent with excitotoxic neural membrane breakdown in these regions.
Assuntos
Encéfalo/metabolismo , Membrana Celular/metabolismo , Fosfolipídeos/metabolismo , Esquizofrenia/metabolismo , Adulto , Antipsicóticos/farmacologia , Antipsicóticos/uso terapêutico , Encéfalo/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Feminino , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Neuroimagem , Esquizofrenia/tratamento farmacológicoRESUMO
BACKGROUND: Thalamic glutamine loss and grey matter reduction suggest neurodegeneration in first-episode schizophrenia, but the duration is unknown. AIMS: To observe glutamine and glutamate levels, grey matter volumes and social functioning in patients with schizophrenia followed to 80 months after diagnosis. METHOD: Grey matter volumes and proton magnetic resonance spectroscopy metabolites in left anterior cingulate and left thalamus were measured in 17 patients with schizophrenia before medication and 10 and 80 months after diagnosis. Social functioning was assessed with the Life Skills Profile Rating Scale (LSPRS) at 80 months. RESULTS: The sum of thalamic glutamate and glutamine levels decreased over 80 months, and correlated inversely with the LSPRS. Thalamic glutamine and grey matter loss were significantly correlated in frontal, parietal, temporal and limbic regions. CONCLUSIONS: Brain metabolite loss is correlated with deteriorated social functioning and grey matter losses in schizophrenia, consistent with neurodegeneration.
Assuntos
Ácido Glutâmico/metabolismo , Glutamina/metabolismo , Giro do Cíngulo , Esquizofrenia , Participação Social , Tálamo , Atividades Cotidianas , Adolescente , Adulto , Análise de Variância , Antipsicóticos/uso terapêutico , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Mapeamento Encefálico , Estudos de Casos e Controles , Feminino , Glutamina/deficiência , Giro do Cíngulo/metabolismo , Giro do Cíngulo/patologia , Humanos , Espectroscopia de Ressonância Magnética/métodos , Masculino , Escalas de Graduação Psiquiátrica , Esquizofrenia/tratamento farmacológico , Esquizofrenia/metabolismo , Esquizofrenia/patologia , Psicologia do Esquizofrênico , Tálamo/metabolismo , Tálamo/patologia , Fatores de TempoRESUMO
Children with autism spectrum disorder (ASD) exhibit characteristic cognitive and behavioral differences, but no systematic pattern of neuroanatomical differences has been consistently found. Recent neurodevelopmental models posit an abnormal early surge in subcortical white matter growth in at least some autistic children, perhaps normalizing by adulthood, but other studies report subcortical white matter deficits. To investigate the profile of these alterations in 3D, we mapped brain volumetric differences using a relatively new method, tensor-based morphometry. 3D T1-weighted brain MRIs of 24 male children with ASD (age: 9.5 years +/- 3.2 SD) and 26 age-matched healthy controls (age: 10.3 +/- 2.4 SD) were fluidly registered to match a common anatomical template. Autistic children had significantly enlarged frontal lobes (by 3.6% on the left and 5.1% on the right), and all other lobes of the brain were enlarged significantly, or at trend level. By analyzing the applied deformations statistically point-by-point, we detected significant gray matter volume deficits in bilateral parietal, left temporal and left occipital lobes (P = 0.038, corrected), trend-level cerebral white matter volume excesses, and volume deficits in the cerebellar vermis, adjacent to volume excesses in other cerebellar regions. This profile of excesses and deficits in adjacent regions may (1) indicate impaired neuronal connectivity, resulting from aberrant myelination and/or an inflammatory process, and (2) help to understand inconsistent findings of regional brain tissue excesses and deficits in autism.
Assuntos
Transtorno Autístico/patologia , Mapeamento Encefálico/métodos , Encéfalo/anormalidades , Adolescente , Encéfalo/fisiopatologia , Criança , Pré-Escolar , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , MasculinoRESUMO
Progressive volumetric losses in schizophrenia may be preceded by abnormal cell membrane metabolism. Longitudinal changes in membrane metabolites were quantified with (31)P MRS in the anterior cingulate and left thalamus of 13 first episode schizophrenic patients and 13 healthy volunteers at baseline and 30 months. Glycerophosphocholine was higher in patients at baseline in the anterior cingulate and glycerophosphoethanolamine was lower in the left thalamus at 30 months compared with patients at baseline and volunteers at 30 months. These observations suggest longitudinal changes in membrane metabolites consistent with a neurodegenerative process in certain cases of schizophrenia.
Assuntos
Glicerilfosforilcolina/metabolismo , Giro do Cíngulo/metabolismo , Fosfatidiletanolaminas/metabolismo , Esquizofrenia/metabolismo , Tálamo/metabolismo , Adulto , Estudos de Casos e Controles , Feminino , Lateralidade Funcional , Humanos , Espectroscopia de Ressonância Magnética/métodos , Masculino , Fósforo/metabolismo , Esquizofrenia/diagnóstico , Fatores de TempoRESUMO
In this study, a computational mapping technique was used to examine the three-dimensional profile of the lateral ventricles in autism. T1-weighted three-dimensional magnetic resonance images of the brain were acquired from 20 males with autism (age: 10.1+/-3.5 years) and 22 male control subjects (age: 10.7+/-2.5 years). The lateral ventricles were delineated manually and ventricular volumes were compared between the two groups. Ventricular traces were also converted into statistical three-dimensional maps, based on anatomical surface meshes. These maps were used to visualize regional morphological differences in the thickness of the lateral ventricles between patients and controls. Although ventricular volumes measured using traditional methods did not differ significantly between groups, statistical surface maps revealed subtle, highly localized reductions in ventricular size in patients with autism in the left frontal and occipital horns. These localized reductions in the lateral ventricles may result from exaggerated brain growth early in life.
Assuntos
Transtorno Autístico/diagnóstico , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Ventrículos Laterais/patologia , Imageamento por Ressonância Magnética , Adolescente , Mapeamento Encefálico , Criança , Dominância Cerebral/fisiologia , Lobo Frontal/patologia , Humanos , Masculino , Lobo Occipital/patologia , Valores de ReferênciaRESUMO
BACKGROUND: Although brain imaging studies have reported neurobiological abnormalities in autism, the nature and distribution of the underlying neurochemical irregularities are unknown. The purpose of this study was to examine cerebral gray and white matter cellular neurochemistry in autism with proton magnetic resonance spectroscopic imaging (MRSI). METHODS: Proton MRSI examinations were conducted in 26 males with autism (age 9.8 +/- 3.2 years) and 29 male comparison subjects (age 11.1 +/- 2.4 years). Estimates of cerebral gray and white matter concentrations of N-acetylaspartate (NAA), creatine + phosphocreatine, choline-containing compounds, myo-inositol, and glutamate + glutamine (Glx) were made by linear regression analysis of multi-slice MRSI data and compared between groups. Regional estimates of metabolite concentration were also made with multivariate linear regression, allowing for comparisons of frontal, temporal, and occipital gray matter, cerebral white matter, and the cerebellum. RESULTS: Patients with autism exhibited significantly lower levels of gray matter NAA and Glx than control subjects. Deficits were widespread, affecting most cerebral lobes and the cerebellum. No significant differences were detected in cerebral white matter or cerebellar metabolite levels. CONCLUSIONS: These results suggest widespread reductions in gray matter neuronal integrity and dysfunction of cortical and cerebellar glutamatergic neurons in patients with autism.
Assuntos
Transtorno Autístico/complicações , Encefalopatias/etiologia , Encefalopatias/patologia , Córtex Cerebral/anormalidades , Córtex Cerebral/patologia , Ressonância Magnética Nuclear Biomolecular , Adolescente , Análise de Variância , Transtorno Autístico/patologia , Córtex Cerebral/metabolismo , Criança , Humanos , Modelos Lineares , Imageamento por Ressonância Magnética/métodos , MasculinoRESUMO
BACKGROUND: Volumetric studies have reported reductions in the size of the corpus callosum (CC) in autism, but the callosal regions contributing to this deficit have differed among studies. In this study, a computational method was used to detect and map the spatial pattern of CC abnormalities in male patients with autism. METHODS: Twenty-four boys with autism (aged 10.0 +/- 3.3 years) and 26 control boys (aged 11.0 +/- 2.5 years) underwent a magnetic resonance imaging (MRI) scan at 3 Tesla. Total and regional areas of the CC were determined using traditional morphometric methods. Three-dimensional (3D) surface models of the CC were also created from the MRI scans. Statistical maps were created to visualize morphologic variability of the CC and to localize regions of callosal thinning in autism. RESULTS: Traditional morphometric methods detected a significant reduction in the total callosal area and in the anterior third of the CC in patients with autism; however, 3D maps revealed significant reductions in both the splenium and genu of the CC in patients. CONCLUSIONS: Statistical maps of the CC revealed callosal deficits in autism with greater precision than traditional morphometric methods. These abnormalities suggest aberrant connections between cortical regions, which is consistent with the hypothesis of abnormal cortical connectivity in autism.
Assuntos
Transtorno Autístico/diagnóstico , Transtorno Autístico/fisiopatologia , Mapeamento Encefálico/métodos , Corpo Caloso/fisiopatologia , Adolescente , Análise de Variância , Criança , Corpo Caloso/anatomia & histologia , Corpo Caloso/patologia , Humanos , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Masculino , Valores de ReferênciaRESUMO
Altered high energy and membrane metabolism, measured with phosphorus magnetic resonance spectroscopy (31P-MRS), has been inconsistently reported in schizophrenic patients in several anatomical brain regions implicated in the pathophysiology of this illness, with little attention to the effects of brain tissue type on the results. Tissue regression analysis correlates brain tissue type to measured metabolite levels, allowing for the extraction of "pure" estimated grey and white matter compartment metabolite levels. We use this tissue analysis technique on a clinical dataset of first episode schizophrenic patients and matched controls to investigate the effect of brain tissue specificity on altered energy and membrane metabolism. In vivo brain spectra from two regions, (a) the fronto-temporal-striatal region and (b) the frontal-lobes, were analyzed from 12 first episode schizophrenic patients and 11 matched controls from a (31)P chemical shift imaging (CSI) study at 4 Tesla (T) field strength. Tissue regression analyses using voxels from each region were performed relating metabolite levels to tissue content, examining phosphorus metabolite levels in grey and white matter compartments. Compared with controls, the first episode schizophrenic patient group showed significantly increased adenosine triphosphate levels (B-ATP) in white matter and decreased B-ATP levels in grey matter in the fronto-temporal-striatal region. No significant metabolite level differences were found in grey or white matter compartments in the frontal cortex. Tissue regression analysis reveals grey and white matter specific aberrations in high-energy phosphates in first episode schizophrenia. Although past studies report inconsistent regional differences in high-energy phosphate levels in schizophrenia, the present analysis suggests more widespread differences that seem to be strongly related to tissue type. Our data suggest that differences in grey and white matter tissue content between past studies may account for some of the variance in the literature.
Assuntos
Encéfalo/metabolismo , Encéfalo/fisiopatologia , Espectroscopia de Ressonância Magnética/métodos , Esquizofrenia/metabolismo , Esquizofrenia/fisiopatologia , Adulto , Manual Diagnóstico e Estatístico de Transtornos Mentais , Feminino , Lobo Frontal/metabolismo , Lobo Frontal/fisiopatologia , Humanos , Masculino , Fósforo , Análise de Regressão , Esquizofrenia/diagnóstico , Fatores de TempoRESUMO
Brain imaging studies of the hippocampus in autism have yielded inconsistent results. In this study, a computational mapping strategy was used to examine the three-dimensional profile of hippocampal abnormalities in autism. Twenty-one males with autism (age: 9.5+/-3.3 years) and 24 male controls (age: 10.3+/-2.4 years) underwent a volumetric magnetic resonance imaging scan at 3 Tesla. The hippocampus was delineated, using an anatomical protocol, and hippocampal volumes were compared between the two groups. Hippocampal traces were also converted into three-dimensional parametric surface meshes, and statistical brain maps were created to visualize morphological differences in the shape and thickness of the hippocampus between groups. Parametric surface meshes and shape analysis revealed subtle differences between patients and controls, particularly in the right posterior hippocampus. These deficits were significant even though the groups did not differ significantly with traditional measures of hippocampal volume. These results suggest that autism may be associated with subtle regional reductions in the size of the hippocampus. The increased statistical and spatial power of computational mapping methods provided the ability to detect these differences, which were not found with traditional volumetric methods.
Assuntos
Transtorno Autístico/diagnóstico , Mapeamento Encefálico , Hipocampo/patologia , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Imageamento por Ressonância Magnética , Adolescente , Transtorno Autístico/patologia , Criança , Dominância Cerebral/fisiologia , Humanos , Masculino , Valores de ReferênciaRESUMO
OBJECTIVE: To use functional magnetic resonance imaging (fMRI) to investigate functional connectivity, and hence, underlying neural networks, in never-treated, first-episode patients with schizophrenia using a word fluency paradigm known to activate prefrontal, anterior cingulate, and thalamic regions. Abnormal connectivity between the prefrontal cortex (PFC) and other brain regions has been demonstrated in chronic, medicated patients in previous positron emission tomography (PET) studies, but has not to our knowledge, previously been demonstrated using both first-episode, drug-naïve patients and fMRI technology. METHODS: A 4.0-Tesla (T) fMRI was used to examine activation and functional connectivity [psychophysiological interactions (PPIs)] during a word fluency task compared to silent reading in 10 never-treated, first-episode patients with schizophrenia and 10 healthy volunteers of comparable age, sex, handedness, and parental education. RESULTS: Compared to healthy volunteers, the schizophrenia patient group exhibited less activation during the word fluency task, mostly in the right anterior cingulate and prefrontal regions. Psychophysiological interactions between right anterior cingulate and other parts of the brain revealed a localized interaction with the left temporal lobe in healthy volunteers during the task and a widespread unfocussed interaction in patients. CONCLUSION: These findings suggest anterior cingulate involvement in the neuronal circuitry underlying schizophrenia.
Assuntos
Encéfalo/fisiopatologia , Imageamento por Ressonância Magnética , Rede Nervosa/fisiopatologia , Esquizofrenia/fisiopatologia , Comportamento Verbal , Vocabulário , Adulto , Manual Diagnóstico e Estatístico de Transtornos Mentais , Feminino , Giro do Cíngulo/fisiopatologia , Humanos , Masculino , Córtex Pré-Frontal/fisiopatologia , Esquizofrenia/diagnóstico , Tálamo/fisiopatologiaRESUMO
OBJECTIVE: Although abnormalities of neural circuits involving the cortex, striatum, and thalamus are hypothesized to underlie Tourette's disorder, the neuronal abnormalities within components of these circuits are unknown. The purpose of this study was to examine the cellular neurochemistry within these circuits in Tourette's disorder using proton magnetic resonance spectroscopy, a method that has not previously been used in neurobiological investigations of the disorder. METHOD: Proton magnetic resonance spectroscopic imaging examinations were conducted in 25 males with Tourette's disorder (age 10.9 +/- 2.0 years) and 32 male comparison subjects (age 11.5 +/- 2.7 years). Spectra from frontal cortex, caudate nucleus, putamen, and thalamus were analyzed, and N-acetylaspartate, creatine, choline, myoinositol, and glutamate + glutamine were quantified and compared between the groups. RESULTS: Patients with Tourette's disorder demonstrated a reduction in N-acetylaspartate and choline in the left putamen, along with reduced levels of creatine bilaterally in the putamen. In the frontal cortex, patients had significantly lower concentrations of N-acetylaspartate bilaterally, lower levels of creatine on the right side, and reduced myoinositol on the left side. CONCLUSIONS: The results of this study suggest compromised neuronal integrity and deficits in density of neuronal and nonneuronal cells in components of the neural circuits implicated in Tourette's disorder.
Assuntos
Encéfalo/fisiopatologia , Metabolismo Energético/fisiologia , Espectroscopia de Ressonância Magnética , Síndrome de Tourette/fisiopatologia , Adolescente , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Mapeamento Encefálico , Criança , Colina/metabolismo , Corpo Estriado/fisiopatologia , Creatina/metabolismo , Dominância Cerebral/fisiologia , Feminino , Lobo Frontal/fisiopatologia , Ácido Glutâmico/metabolismo , Glutamina/metabolismo , Humanos , Inositol/metabolismo , Masculino , Rede Nervosa/fisiopatologia , Neurônios/fisiologia , Valores de Referência , Tálamo/fisiopatologia , Síndrome de Tourette/diagnósticoRESUMO
OBJECTIVE: This in vivo (1)H magnetic resonance spectroscopy study examined levels of glutamate, glutamine, and N-acetylaspartate in medicated patients with chronic schizophrenia. METHOD: Localized in vivo (1)H spectra were acquired at 4.0 T from the left anterior cingulate and thalamus of 21 patients with schizophrenia and 21 comparable healthy volunteers. RESULTS: Significantly lower levels of glutamine and glutamate were found in the left anterior cingulate cortex of patients with schizophrenia than in the healthy volunteers. For the schizophrenia patients, the glutamine level in the left thalamus was found to be higher than normal, and there was a significant negative correlation between N-acetylaspartate level and duration of positive symptoms. CONCLUSIONS: Since previous studies have found higher than normal levels of glutamine in the left anterior cingulate of never-treated patients, decreased levels of these metabolites in chronic patients could be related to neurodegeneration or the effects of chronic medication.
Assuntos
Antipsicóticos/uso terapêutico , Ácido Aspártico/análogos & derivados , Ácido Glutâmico/metabolismo , Glutamina/metabolismo , Giro do Cíngulo/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Esquizofrenia/tratamento farmacológico , Tálamo/efeitos dos fármacos , Adulto , Antipsicóticos/efeitos adversos , Ácido Aspártico/metabolismo , Doença Crônica , Dominância Cerebral/fisiologia , Feminino , Giro do Cíngulo/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Degeneração Neural/diagnóstico , Degeneração Neural/fisiopatologia , Escalas de Graduação Psiquiátrica , Valores de Referência , Esquizofrenia/diagnóstico , Esquizofrenia/fisiopatologia , Tálamo/fisiopatologiaRESUMO
OBJECTIVE: This in vivo (1)H magnetic resonance spectroscopy study examined levels of glutamate, glutamine, and N-acetylaspartate in patients experiencing their first episode of schizophrenia. METHOD: Localized in vivo (1)H spectra were acquired at 4.0 T from the left anterior cingulate and thalamus of 21 never-treated patients with schizophrenia and 21 comparable healthy volunteers. RESULTS: The level of glutamine was significantly higher in the left anterior cingulate cortex and thalamus of the patients with schizophrenia than in the healthy subjects. No differences were found between groups in the levels of other metabolites in the anterior cingulate or thalamus. CONCLUSIONS: Higher than normal glutamine levels in the left anterior cingulate and thalamus provide in vivo evidence of greater than normal glutamatergic activity proposed by glutamatergic models of schizophrenia. In contrast to other studies in chronically ill patients, no differences were seen in the levels of N-acetylaspartate in either location, suggesting that the findings in patients with chronic schizophrenia may be related to the effect of medication or the progression of the illness.
Assuntos
Dominância Cerebral/fisiologia , Ácido Glutâmico/metabolismo , Glutamina/metabolismo , Giro do Cíngulo/patologia , Espectroscopia de Ressonância Magnética , Esquizofrenia/patologia , Psicologia do Esquizofrênico , Tálamo/patologia , Adulto , Feminino , Humanos , Masculino , Escalas de Graduação Psiquiátrica , Valores de Referência , Esquizofrenia/diagnósticoRESUMO
AAPM Magnetic Resonance Task Group #9 on proton magnetic resonance spectroscopy (MRS) in the brain was formed to provide a reference document for acquiring and processing proton (1H) MRS acquired from brain tissue. MRS is becoming a common adjunct to magnetic resonance imaging (MRI), especially for the differential diagnosis of tumors in the brain. Even though MR imaging is an offshoot of MR spectroscopy, clinical medical physicists familiar with MRI may not be familiar with many of the common practical issues regarding MRS. Numerous research laboratories perform in vivo MRS on other magnetic nuclei, such as 31P, 13C, and 19F. However, most commercial MR scanners are generally only capable of spectroscopy using the signals from protons. Therefore this paper is of limited scope, giving an overview of technical issues that are important to clinical proton MRS, discussing some common clinical MRS problems, and suggesting how they might be resolved. Some fundamental issues covered in this paper are common to many forms of magnetic resonance spectroscopy and are written as an introduction for the reader to these methods. These topics include shimming, eddy currents, spatial localization, solvent saturation, and post-processing methods. The document also provides an extensive review of the literature to guide the practicing medical physicist to resources that may be useful for dealing with issues not covered in the current article.
Assuntos
Química Encefálica , Encéfalo/metabolismo , Aumento da Imagem/instrumentação , Aumento da Imagem/métodos , Espectroscopia de Ressonância Magnética/instrumentação , Espectroscopia de Ressonância Magnética/métodos , Artefatos , Calibragem , Análise de Falha de Equipamento , Análise de Fourier , Humanos , Lipídeos/química , Espectroscopia de Ressonância Magnética/normas , Imagens de Fantasmas , Prótons , Controle de Qualidade , Processos Estocásticos , Água/químicaRESUMO
Functional MR imaging (fMRI) based upon the Blood Oxygen Level Dependent (BOLD) effect is currently an important new tool for understanding basic brain function and specifically allowing the correlation of physiological activity with anatomical location without the use of ionizing radiation. The clinical role of fMRI is still being defined and is the subject of much research activity. In this report we present the underlying physical, technical and mathematical principals of BOLD fMRI along with descriptions of typical applications. Our purpose in this report is to provide, in addition to basic principles, an insight into the aspects of BOLD imaging, which may be used by the medical physicist to assist in the implement of fMRI procedures in either a hospital or research environment.
Assuntos
Encefalopatias/diagnóstico , Encefalopatias/fisiopatologia , Encéfalo/anatomia & histologia , Imageamento por Ressonância Magnética/instrumentação , Imageamento por Ressonância Magnética/métodos , Oxigênio/sangue , Encéfalo/fisiopatologia , Circulação Cerebrovascular , Humanos , Aumento da Imagem , Marcadores de SpinRESUMO
This study used high-field magnetic resonance spectroscopy to examine the correlation of 1H and 31P metabolite levels in patients with schizophrenia and normal controls. 1H and 31P in vivo spectra were acquired successively from the left anterior cingulate and left thalamus of nine chronic schizophrenic patients and eight comparable healthy controls. A significant positive correlation between glutamine (Gln) and phosphoethanolamine (PEtn) was found in the left anterior cingulate of patients. In the left thalamus of patients, a significant negative correlation between N-acetylaspartate (NAA) and glycerophosphocholine (GroPCho) was found. No significant correlations were found in controls. The correlation between glutamine and phosphoethanolamine may reflect a link between neurotransmission alterations and membrane phospholipid metabolism alterations. The negative correlation between N-acetylaspartate and glycerophosphocholine may reflect the presence of neurodegeneration.
Assuntos
Encéfalo/metabolismo , Espectroscopia de Ressonância Magnética , Fosfolipídeos/metabolismo , Fósforo/farmacocinética , Prótons , Esquizofrenia/diagnóstico , Adulto , Humanos , Masculino , Degeneração Neural/patologia , Fósforo/administração & dosagem , Esquizofrenia/patologiaRESUMO
N-acetylaspartate (NAA) has been associated with neuronal integrity and function, and choline-containing compounds have been linked to neuronal membrane integrity. This study examined the influence of the duration of untreated psychosis, duration of prodromal symptoms and total length of untreated illness on these markers of neuronal loss or damage. In vivo 1H magnetic resonance spectroscopy data were acquired from 1.5-cc volumes in the left anterior cingulate and left thalamus of 19 never-treated first episode schizophrenic subjects using STEAM20 at 4.0 Tesla. Duration of untreated psychosis, prodrome and total length of untreated illness were correlated with levels of NAA and choline. No significant correlation was observed between NAA and duration of untreated psychosis and untreated illness in both regions examined. Thalamic NAA negatively correlated with duration of prodromal symptoms. A positive correlation between choline and duration of untreated psychosis was identified in both regions studied. Delays in treatment of psychotic symptoms of schizophrenia were not associated with a reduction in markers of neuronal integrity or function in contrast to longer prodromal periods, which were associated with lower NAA. Neuronal damage, potentially detectable via lower NAA, may be occurring before the onset of psychosis. Increased choline is associated with longer duration of untreated psychosis and could indicate that psychosis-related membrane alterations precede the appearance of NAA reductions observed by studies of chronic schizophrenia.
Assuntos
Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Encéfalo/fisiopatologia , Morte Celular/fisiologia , Colina/metabolismo , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Esquizofrenia/diagnóstico , Psicologia do Esquizofrênico , Adolescente , Adulto , Encéfalo/patologia , Estudos de Coortes , Dominância Cerebral/fisiologia , Feminino , Seguimentos , Humanos , Masculino , Neurônios/patologia , Escalas de Graduação Psiquiátrica , Valores de Referência , Esquizofrenia/fisiopatologia , Transtorno da Personalidade Esquizotípica/diagnóstico , Transtorno da Personalidade Esquizotípica/fisiopatologia , Transtorno da Personalidade Esquizotípica/psicologia , Estatística como Assunto , Fatores de TempoRESUMO
Functional magnetic resonance imaging (fMRI) was used to investigate the dose-response relationship (sham, 100, 200, 1000 microT) between a pulsed extremely low frequency magnetic field (ELFMF) and acute thermal pain on the dominant right hand. Forty-seven participants were recruited, and pulsed ELFMF was applied through the MRI gradient system using a novel technique. Regions of interest (ROIs) matching those of previous studies were examined for a potential dose response. Significant correlations between applied field strength and change in BOLD activity were found in the anterior cingulate and the ipsilateral insula, indicating that there might be either a dose response or a threshold effect of the ELFMF.
Assuntos
Encéfalo/efeitos da radiação , Campos Eletromagnéticos , Dor/fisiopatologia , Doença Aguda , Adulto , Encéfalo/fisiopatologia , Mapeamento Encefálico , Relação Dose-Resposta à Radiação , Humanos , Imageamento por Ressonância Magnética , Percepção da Dor , Temperatura , Adulto JovemRESUMO
Extremely low-frequency magnetic fields (from DC to 300 Hz) have been shown to affect pain sensitivity in snails, rodents and humans. Here, a functional magnetic resonance imaging study demonstrates how the neuromodulation effect of these magnetic fields influences the processing of acute thermal pain in normal volunteers. Significant interactions were found between pre- and post-exposure activation between the sham and exposed groups for the ipsilateral (right) insula, anterior cingulate and bilateral hippocampus/caudate areas. These results show, for the first time, that the neuromodulation induced by exposure to low-intensity low-frequency magnetic fields can be observed in humans using functional brain imaging and that the detection mechanism for these effects may be different from those used by animals for orientation and navigation. Magnetoreception may be more common than presently thought.
Assuntos
Campos Eletromagnéticos/efeitos adversos , Exposição Ambiental/análise , Dor , Transmissão Sináptica/efeitos da radiação , Adolescente , Adulto , Encéfalo/patologia , Encéfalo/efeitos da radiação , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Estimulação FísicaRESUMO
BACKGROUND: Progressive volumetric changes in the brains of people with schizophrenia have been attributed to a number of factors. AIMS: To determine whether glutamatergic changes in patients with schizophrenia correlated with grey-matter losses during the first years of illness. METHOD: Left anterior cingulate and thalamic glutamatergic metabolite levels and grey-matter volumes were examined in 16 patients with first-episode schizophrenia before and after 10 months and 30 months of antipsychotic treatment and in 16 healthy participants on two occasions 30 months apart. RESULTS: Higher than normal glutamine levels were found in the anterior cingulate and thalamus of never-treated patients. Thalamic levels of glutamine were significantly reduced after 30 months. Limited grey-matter reductions were seen in patients at 10 months followed by widespread grey-matter loss at 30 months. Parietal and temporal lobe grey-matter loss was correlated with thalamic glutamine loss. CONCLUSIONS: Elevated glutamine levels in never-treated patients followed by decreased thalamic glutamine and grey-matter loss in connected regions could indicate either neurodegeneration or a plastic response to reduced subcortical activity.